One of the most widespread forms of renewable energy is wind power, which relies on wind as the primary energy source.
The devices most commonly used to transform wind energy into electricity are multibladed wind turbines. Despite the clear and undeniable technological improvements continuously achieved, these systems suffer from four fundamental drawbacks:
a) As they have mechanical components, gears, windings, etc. they have maintenance costs due to consumption of lubricants, part wear, heat degradation of insulating resins and other effects related to friction, heating due to friction, etc.
b) Conventional multibladed wind turbines, based on theoretical work performed by Betz in 1927, increase their efficiency the higher the rotation speed of the rotors. This, in conjunction with the fact that the amount of energy available in a circular surface increases with the square of the blade length, means that the speed at the tips of the blades is very high, representing a high risk to avian fauna, with numerous accidents having been observed.
c) The deliberate increase in size is translated into a substantial increase in the complexity of its assembly, increasing initial installation costs.
d) The subjective visual impact of wind turbines can be described in many ways, but in any case their presence is increased by their wide range of motion.
In order to improve these aspects, the present invention describes a device based on three physical principals or foundations. These principles are widely used separately in the industry:
The first principle is electromechanical coupling. This effect is exhibited by certain materials in which when a force is applied between two of their faces a potential difference is created between them. As with any electrical machine, its operation is reversible and the presence of a voltage between two of its faces causes a deformation. Among these materials are ferroelectric materials (such as lead zirconate titanate and its derivatives) and piezoelectric materials (certain crystals such as quartz, etc.).
Materials with some type of electromechanical coupling have a wide range of applications as actuators (positioners, motors), speakers (introducing electrical energy and obtaining mechanical energy) and as sensors for pressure, position, contact, deformation and transducers of various types (in which mechanical energy is introduced to obtain electrical energy).
Their application in the generation of electrical energy is not so widespread, but there already exist pavements and floors walked on by pedestrians that transform the energy of their steps into usable electrical energy. There are proposals for clothing, footwear and even silicone implants that obtain energy from the movement of the body and use it to recharge portable electronic devices. They have been used for some time in electric arc lighters to produce the lighting spark in lighters, keyboards that recharge the device that they are included in with the user's keystrokes, etc. Similarly, there are designs for an electricity generator that intends to gather the pulsing and turbulent energy from the impact of waves or wind.
A second principle is the deliberate generation of turbulent vortices from a non-turbulent laminar flow. The “Karman vortex street” was described by the Hungarian scientist Theodore von Karman in 1911, and its most used technological application is a specific type of flowmeter known as a vortex flowmeter, which measures the amount of fluid passing through a conduct by counting the number of vortices formed inside it due to the presence of an element with a known geometry. The knowledge and modelling of this principle is also used in atmospheric and oceanic forecasting.
The third principle relates to the natural oscillation frequency of bodies. It is applied intentionally in the manufacture of musical instruments, loudspeakers, electronic devices (resonators), in some applications in microscopy (“tapping” in AFM, MRFM microscopes etc., which have a cantilever that oscillates harmonically to improve the reading from the tip), etc. On the other hand, it is an effect that is avoided if possible in other technological areas, such as automotion and mechanics (Structural Acoustic
Coupling Control) to reduce engine noise, in brake pads, etc. It is also an undesired effect in architecture and large structures, such as chimneys or bridges (as in the famous and exemplary case of the Tacoma Narrows bridge or the Ferrybridge nuclear plant cooling tower, where the aforementioned Karman vortices were also generated), etc.
No wind turbine generator device has been found which, in its geometry, intentionally seeks to synchronise the appearance of the turbulent vortices that appear throughout its structure.
No electrical generator has been found to date that purposely seeks the natural oscillation of bodies as an operational principle. None establishes in a controlled manner tunings or resonance of any type between their natural oscillation frequency and the frequency at which turbulent vortices are generated.
To this date no electrical generator of those based on materials with electromechanical coupling has been found to date that uses as primary energy source the energy contained in a stationary laminar airflow.